US6466037B1 - Method for determining the load in a tumble dryer - Google Patents

Method for determining the load in a tumble dryer Download PDF

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Publication number
US6466037B1
US6466037B1 US09/138,348 US13834898A US6466037B1 US 6466037 B1 US6466037 B1 US 6466037B1 US 13834898 A US13834898 A US 13834898A US 6466037 B1 US6466037 B1 US 6466037B1
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US
United States
Prior art keywords
frequency
measurement signal
pulsed
laundry
conductivity measurement
Prior art date
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Expired - Fee Related
Application number
US09/138,348
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English (en)
Inventor
Hansjörg Meerpohl
Dietmar Pech
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BSH Hausgeraete GmbH
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BSH Bosch und Siemens Hausgeraete GmbH
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Assigned to BSH BOSCH UND SIEMENS HAUSGERATE GMBH reassignment BSH BOSCH UND SIEMENS HAUSGERATE GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MEERPOHL, HANSJORG, PECH, DIETMAR
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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F34/00—Details of control systems for washing machines, washer-dryers or laundry dryers
    • D06F34/04—Signal transfer or data transmission arrangements
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F2103/00—Parameters monitored or detected for the control of domestic laundry washing machines, washer-dryers or laundry dryers
    • D06F2103/02—Characteristics of laundry or load
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F2103/00—Parameters monitored or detected for the control of domestic laundry washing machines, washer-dryers or laundry dryers
    • D06F2103/02—Characteristics of laundry or load
    • D06F2103/08—Humidity
    • D06F2103/10—Humidity expressed as capacitance or resistance
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F58/00—Domestic laundry dryers
    • D06F58/32—Control of operations performed in domestic laundry dryers 
    • D06F58/34—Control of operations performed in domestic laundry dryers  characterised by the purpose or target of the control
    • D06F58/36—Control of operational steps, e.g. for optimisation or improvement of operational steps depending on the condition of the laundry
    • D06F58/38—Control of operational steps, e.g. for optimisation or improvement of operational steps depending on the condition of the laundry of drying, e.g. to achieve the target humidity

Definitions

  • the present invention relates to a method for determining a load in a tumble dryer.
  • the tumble dryer is provided with electrodes for determining the electrical conductivity of laundry in the tumble dryer.
  • the load in the tumble dryer also plays a major part in the drying process. It is therefore advantageous for various reasons to determine the load in the tumble dryer, for example in order to predict the remaining time accurately, in order to control the drying process in an optimum fashion or in order to output a heating capacity that is matched to the heating requirement.
  • the prior art discloses methods of determining the load in tumble dryers which are based on the evaluation of temperature measurements or temperature gradient measurements, on the current demand of the motor to move the laundry drum or on a measurement of the electrical capacitance of the drum.
  • the integral of the hit signals therefore constitutes a measure of the load in the tumble dryer, which can be used for controlling the drying process.
  • the use of a simple threshold value circuit may give rise to the situation where, as a result of the low conductivity difference between a contact and a non-contact measurement of a piece of laundry engaging the electrodes, it may not be possible to register the contact of the laundry.
  • a method for determining a load in a tumble dryer which includes: moving laundry in a laundry drum having electrodes; generating a pulsed conductivity measurement signal measuring electrical conductivity of the laundry as a result of contact occurring at least from time to time between the laundry and the electrodes of the laundry drum; and determining a frequency of the pulsed conductivity measurement signal, the frequency serving as a measure of a load of the laundry.
  • the frequency of the pulses in the measurement signal of the electrical conductivity of the laundry is determined and used as a measure of the load.
  • the load can then be taken into account for controlling the drying process.
  • the signal edges of the conductivity measurement signal are registered in particular by forming a time derivative (differentiation), and the frequency of the conductivity measurement signal is determined by determining the frequency of the registered edges.
  • the pulses of the conductivity measurement signal are compared with a threshold value and, by counting the pulses above or below a specific threshold value per unit of time, the frequency of the pulses which fall above or below the threshold value is determined. Since the comparison with a threshold value can be implemented particularly simply in terms of circuitry by using a comparator or a Schmitt trigger, it is possible in implement the invention in a particularly simply and cost-effectively manner.
  • the frequency of the pulses are then determined and used as a measure of the load.
  • the triggering pulses of constant duration avoids the occurrence of extremely short or extremely long pulses which make a reliable determination of the load more difficult in the case of a limited reaction time capability of the components.
  • the determination of the frequency of the pulses of the conductivity measurement signal is carried out by a microcontroller. This enables the frequency to be determined with a low outlay for components and, as the central control device in the tumble dryer, the microcontroller can directly use the necessary information about the load.
  • each of the above-mentioned steps in the course of processing the conductivity measurement signal in order to determine the frequency of its pulses can advantageously also be implemented in a digital electronic arithmetic unit or a microcontroller.
  • the fact that the function is carried out in a microcontroller that is already present in the dryer results in a savings in components and circuitry, which also leads to a lower probability of failure of the tumble dryer.
  • the determination of the frequency of the pulses of the conductivity measurement signal can be carried out particularly advantageously with the microcontroller.
  • the frequency measurement, of whatever pulses or events can be carried out with a very low outlay on circuitry and very high accuracy using the microcontroller, since the latter, in comparison with analog circuits, is able to process just the digital signals particularly advantageously.
  • the comparison of the conductivity measurement signal with a predetermined threshold value may be carried out particularly advantageously with the microcontroller.
  • an analog/digital convertor that is assigned to the microcontroller or implemented in it or else a special input to the microcontroller, such as an input with a Schmitt trigger or comparator, which can execute the comparison function.
  • the analog/digital convertor may be assigned externally to the microcontroller or else integrated in the microcontroller. If use is made of a microcontroller with an associated analog/digital convertor, all of the previously mentioned methods can be carried out as a result of the capability of processing both the analog and digital signals, so that it is also possible for a plurality of the above-mentioned methods to be applied in the tumble dryer.
  • FIGURE of the drawing a block circuit diagram of a structure for carrying out one embodiment of the method according to the invention.
  • a drum 1 with a first electrode 12 the drum 1 itself serving as a second electrode.
  • the drum 1 is connected to a ground 5 of the tumble dryer, and the first electrode 12 is connected via a bias resistor 13 to a constant voltage 6 .
  • the laundry in the drum 1 has a laundry resistance 14 , which on one side is connected via the drum 1 to the ground 5 of the tumble dryer. On the other side, the laundry is connected via the electrode 12 to the resistor 13 , and therefore forms a voltage divider with the latter.
  • a measured signal 15 is obtained which serves as a measure of the conductivity of the laundry.
  • the measured conductivity signal 15 is connected to an input of a differential element 2 , which generates an output signal 21 .
  • the output signal 21 from the differential element 2 is in turn connected to an input of a monostable multivibrator 3 , whose output signal 31 is connected to an input of a microcontroller 4 .
  • the load in the tumble dryer is determined during the movement of the laundry in the drum 1 as a result of its rotation.
  • the laundry touches the first electrode 12 , at least from time to time, which results in the measured conductivity signal 15 that varies with time.
  • the measured conductivity signal 15 will exhibit a jump or a pulse.
  • the number of the pulses per unit of time is a measure of the load in the tumble dryer. Since the measured conductivity signal 15 is very irregular, and the determination of the frequency of the pulses is difficult, the signal must be suitably conditioned.
  • the slope of the pulses of the measured conductivity signal 15 is determined, and thus that of its flanks is registered, using the differential element 2 .
  • Each of the registered edges, which are contained in the output signal 21 from the differential element 2 triggers the monostable multivibrator 3 to output a pulse signal 31 of constant duration.
  • the output signal 31 from the monostable multivibrator 3 which exhibits the pulses of constant duration, is connected to a digital input of the microcontroller 4 .
  • the microcontroller 4 counts the pulses received per unit of time in the signal 31 and thus determines the frequency, which is a direct measure of the load.
  • the novel solution provides a method for determining the load in a tumble dryer with which the measure of the load is present in digital form.
  • simpler processing by digital modules, in particular by the microcontroller 4 and a more precise determination of the load are possible.
  • the microcontroller 4 for controlling the drying operation, it is in this way possible for the necessary information about the load to be directly available in the microcontroller 4 .

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Textile Engineering (AREA)
  • Control Of Washing Machine And Dryer (AREA)
  • Measurement Of Resistance Or Impedance (AREA)
US09/138,348 1997-08-21 1998-08-21 Method for determining the load in a tumble dryer Expired - Fee Related US6466037B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19736422 1997-08-21
DE19736422A DE19736422A1 (de) 1997-08-21 1997-08-21 Verfahren zur Bestimmung der Beladungsmenge eines Wäschetrockners

Publications (1)

Publication Number Publication Date
US6466037B1 true US6466037B1 (en) 2002-10-15

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Application Number Title Priority Date Filing Date
US09/138,348 Expired - Fee Related US6466037B1 (en) 1997-08-21 1998-08-21 Method for determining the load in a tumble dryer

Country Status (3)

Country Link
US (1) US6466037B1 (fr)
EP (1) EP0898008B1 (fr)
DE (2) DE19736422A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040168343A1 (en) * 2002-11-26 2004-09-02 Park Sang Ho Laundry drier
US20060242858A1 (en) * 2005-04-28 2006-11-02 Mabe Canada Inc. Apparatus and method for controlling a clothes dryer
US20090260256A1 (en) * 2008-04-18 2009-10-22 Mabe Canada Inc. Apparatus for controlling a clothes dryer
RU2459020C2 (ru) * 2007-04-30 2012-08-20 Электролюкс Хоум Продактс Корпорейшн Н.В. Способ управления барабанной сушилкой для белья
US8578627B2 (en) 2010-10-21 2013-11-12 Whirlpool Corporation Method and apparatus for moisture sensor noise immunity
JP2014057767A (ja) * 2012-09-19 2014-04-03 Panasonic Corp ドラム式洗濯乾燥機
JP2014057768A (ja) * 2012-09-19 2014-04-03 Panasonic Corp 衣類乾燥機

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19960310A1 (de) * 1999-12-14 2001-06-28 Bsh Bosch Siemens Hausgeraete Vorrichtung und Verfahren zur Messung der Beladung in einem Wäschebehandlungsgerät
DE10200975C2 (de) * 2001-03-02 2003-08-28 Whirlpool Co Verfahren zum Verändern des Programmablaufes bei einem Haushaltswäschetrockner
KR100480929B1 (ko) * 2003-08-12 2005-04-07 엘지전자 주식회사 의류건조기의 건조 제어방법
DE102008025496A1 (de) * 2008-05-28 2009-12-03 BSH Bosch und Siemens Hausgeräte GmbH Messanordnung zur Ermittlung einer Information über die Beladung eines Wäschetrockners
DE102008041265A1 (de) * 2008-08-14 2010-02-18 BSH Bosch und Siemens Hausgeräte GmbH Kondensationstrockner mit einer Wärmepumpe und Erkennung eines unzulässigen Betriebszustands

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2945696A1 (de) 1979-11-13 1981-05-21 Ako-Werke Gmbh & Co., 7988 Wangen Schaltungsanordnung
EP0067896A1 (fr) 1981-06-19 1982-12-29 V - Zug A.G. Procédé pour le séchage de linge et machine pour la mise en oeuvre du procédé
US4422247A (en) * 1981-06-29 1983-12-27 Whirlpool Corporation Low voltage sensor for a dryer
EP0226209A2 (fr) 1985-12-16 1987-06-24 Kabushiki Kaisha Toshiba Séchoir
US5450015A (en) * 1994-02-24 1995-09-12 Forte Technology, Inc. Apparatus for measuring impedance to determine a property of a material
US5514973A (en) * 1994-07-11 1996-05-07 The United States Of America As Represented By The Secretary Of Agriculture System for analyzing moisture content of materials such as cotton

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4403625C2 (de) * 1994-02-05 2003-08-07 Miele & Cie Wäschetrockner mit einer Vorrichtung zur Ermittlung des Füllgrades in der Trommel

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2945696A1 (de) 1979-11-13 1981-05-21 Ako-Werke Gmbh & Co., 7988 Wangen Schaltungsanordnung
EP0067896A1 (fr) 1981-06-19 1982-12-29 V - Zug A.G. Procédé pour le séchage de linge et machine pour la mise en oeuvre du procédé
US4422247A (en) * 1981-06-29 1983-12-27 Whirlpool Corporation Low voltage sensor for a dryer
EP0226209A2 (fr) 1985-12-16 1987-06-24 Kabushiki Kaisha Toshiba Séchoir
US5450015A (en) * 1994-02-24 1995-09-12 Forte Technology, Inc. Apparatus for measuring impedance to determine a property of a material
US5514973A (en) * 1994-07-11 1996-05-07 The United States Of America As Represented By The Secretary Of Agriculture System for analyzing moisture content of materials such as cotton

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040168343A1 (en) * 2002-11-26 2004-09-02 Park Sang Ho Laundry drier
US6928749B2 (en) * 2002-11-26 2005-08-16 Lg Electronics Inc. Laundry dryer
US20060242858A1 (en) * 2005-04-28 2006-11-02 Mabe Canada Inc. Apparatus and method for controlling a clothes dryer
US7322126B2 (en) 2005-04-28 2008-01-29 Mabe Canada Inc. Apparatus and method for controlling a clothes dryer
US20080052954A1 (en) * 2005-04-28 2008-03-06 Mabe Canada Inc. Apparatus and method for controlling a clothes dryer
US7971371B2 (en) * 2005-04-28 2011-07-05 Mabe Canada Inc. Apparatus and method for controlling a clothes dryer
US7975401B2 (en) 2005-04-28 2011-07-12 Mabe Canada Inc. Apparatus and method for controlling a clothes dryer
RU2459020C2 (ru) * 2007-04-30 2012-08-20 Электролюкс Хоум Продактс Корпорейшн Н.В. Способ управления барабанной сушилкой для белья
US20090260256A1 (en) * 2008-04-18 2009-10-22 Mabe Canada Inc. Apparatus for controlling a clothes dryer
US8578627B2 (en) 2010-10-21 2013-11-12 Whirlpool Corporation Method and apparatus for moisture sensor noise immunity
JP2014057767A (ja) * 2012-09-19 2014-04-03 Panasonic Corp ドラム式洗濯乾燥機
JP2014057768A (ja) * 2012-09-19 2014-04-03 Panasonic Corp 衣類乾燥機

Also Published As

Publication number Publication date
EP0898008B1 (fr) 2002-06-26
EP0898008A1 (fr) 1999-02-24
DE19736422A1 (de) 1999-02-25
DE59804563D1 (de) 2002-08-01

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